The Research Methods Core (RMC) aims to advance rigorous mixed methods for improving.knowledge about implementation processes and outcomes of State rollouts of evidence-based practices (EBPs) for children. We propose to use integrative mixed method quantitative and qualitative approaches applied to multilevel processes as framed by the PRISM model. The RMC will provide support to all activities of the Center including mentoring of new and eariy stage investigators, the Accelerated Policy Analysis Unit, and the 3 core studies (3 R34s) and Center pilots.